Isfahan University of Medical SciencesDental Research Journal1735-33278520120317Effect of clearfil protect bond and transbond plus self-etch primer on shear bond strength of orthodontic brackets949949ENS.HamidRajiRezaGhorbanipourPostgraduate Student, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran. dr_ghorbanipour@yahoo.comFatemeMajdzade20120317Background: The aim of this study was to evaluate the shear bond strength of an antimicrobial and fluoride-releasing self-etch primer (clearfil protect bond) and compare it with transbond plus self-etch primer and conventional acid etching and priming system. Materials and Methods: Forty-eight extracted human premolars were divided randomly to three groups. In group 1, the teeth were bonded with conventional acid etching and priming method. In group 2, the teeth were bonded with clearfil protect bond self-etch primer, and transbond plus self-etch primer was used to bond the teeth in group 3. The samples were stored in 37&deg;C distilled water and thermocycled. Then, the SBS of the sample was evaluated with Zwick testing machine. Descriptive statistics and the analysis of variances (ANOVA) and Tukey's test and Kruskal-Walliswere used to analyze the data. Results: The results of the ANOVA showed that the mean of group 3 was significantly lower than that of other groups. Most of the sample showed a pattern of failure within the adhesive resin. Conclusion: The shear bond strength of clearfil protect bond and transbond plus self-etch primer was enough for bonding the orthodontic brackets. The mode of failure of bonded brackets with these two self-etch primers is safe for enamel. Key Words: Acid etching, antimicrobial, bond strength, fluoride, self etch primer